1 // SPDX-License-Identifier: GPL-2.0 2 /***************************************************************************** 3 * USBLCD Kernel Driver * 4 * Version 1.05 * 5 * (C) 2005 Georges Toth <g.toth@e-biz.lu> * 6 * * 7 * This file is licensed under the GPL. See COPYING in the package. * 8 * Based on usb-skeleton.c 2.0 by Greg Kroah-Hartman (greg@kroah.com) * 9 * * 10 * * 11 * 28.02.05 Complete rewrite of the original usblcd.c driver, * 12 * based on usb_skeleton.c. * 13 * This new driver allows more than one USB-LCD to be connected * 14 * and controlled, at once * 15 *****************************************************************************/ 16 #include <linux/module.h> 17 #include <linux/kernel.h> 18 #include <linux/slab.h> 19 #include <linux/errno.h> 20 #include <linux/mutex.h> 21 #include <linux/uaccess.h> 22 #include <linux/usb.h> 23 24 #define DRIVER_VERSION "USBLCD Driver Version 1.05" 25 26 #define USBLCD_MINOR 144 27 28 #define IOCTL_GET_HARD_VERSION 1 29 #define IOCTL_GET_DRV_VERSION 2 30 31 32 static DEFINE_MUTEX(lcd_mutex); 33 static const struct usb_device_id id_table[] = { 34 { .idVendor = 0x10D2, .match_flags = USB_DEVICE_ID_MATCH_VENDOR, }, 35 { }, 36 }; 37 MODULE_DEVICE_TABLE(usb, id_table); 38 39 static DEFINE_MUTEX(open_disc_mutex); 40 41 42 struct usb_lcd { 43 struct usb_device *udev; /* init: probe_lcd */ 44 struct usb_interface *interface; /* the interface for 45 this device */ 46 unsigned char *bulk_in_buffer; /* the buffer to receive 47 data */ 48 size_t bulk_in_size; /* the size of the 49 receive buffer */ 50 __u8 bulk_in_endpointAddr; /* the address of the 51 bulk in endpoint */ 52 __u8 bulk_out_endpointAddr; /* the address of the 53 bulk out endpoint */ 54 struct kref kref; 55 struct semaphore limit_sem; /* to stop writes at 56 full throttle from 57 using up all RAM */ 58 struct usb_anchor submitted; /* URBs to wait for 59 before suspend */ 60 }; 61 #define to_lcd_dev(d) container_of(d, struct usb_lcd, kref) 62 63 #define USB_LCD_CONCURRENT_WRITES 5 64 65 static struct usb_driver lcd_driver; 66 67 68 static void lcd_delete(struct kref *kref) 69 { 70 struct usb_lcd *dev = to_lcd_dev(kref); 71 72 usb_put_dev(dev->udev); 73 kfree(dev->bulk_in_buffer); 74 kfree(dev); 75 } 76 77 78 static int lcd_open(struct inode *inode, struct file *file) 79 { 80 struct usb_lcd *dev; 81 struct usb_interface *interface; 82 int subminor, r; 83 84 mutex_lock(&lcd_mutex); 85 subminor = iminor(inode); 86 87 interface = usb_find_interface(&lcd_driver, subminor); 88 if (!interface) { 89 mutex_unlock(&lcd_mutex); 90 printk(KERN_ERR "USBLCD: %s - error, can't find device for minor %d\n", 91 __func__, subminor); 92 return -ENODEV; 93 } 94 95 mutex_lock(&open_disc_mutex); 96 dev = usb_get_intfdata(interface); 97 if (!dev) { 98 mutex_unlock(&open_disc_mutex); 99 mutex_unlock(&lcd_mutex); 100 return -ENODEV; 101 } 102 103 /* increment our usage count for the device */ 104 kref_get(&dev->kref); 105 mutex_unlock(&open_disc_mutex); 106 107 /* grab a power reference */ 108 r = usb_autopm_get_interface(interface); 109 if (r < 0) { 110 kref_put(&dev->kref, lcd_delete); 111 mutex_unlock(&lcd_mutex); 112 return r; 113 } 114 115 /* save our object in the file's private structure */ 116 file->private_data = dev; 117 mutex_unlock(&lcd_mutex); 118 119 return 0; 120 } 121 122 static int lcd_release(struct inode *inode, struct file *file) 123 { 124 struct usb_lcd *dev; 125 126 dev = file->private_data; 127 if (dev == NULL) 128 return -ENODEV; 129 130 /* decrement the count on our device */ 131 usb_autopm_put_interface(dev->interface); 132 kref_put(&dev->kref, lcd_delete); 133 return 0; 134 } 135 136 static ssize_t lcd_read(struct file *file, char __user * buffer, 137 size_t count, loff_t *ppos) 138 { 139 struct usb_lcd *dev; 140 int retval = 0; 141 int bytes_read; 142 143 dev = file->private_data; 144 145 /* do a blocking bulk read to get data from the device */ 146 retval = usb_bulk_msg(dev->udev, 147 usb_rcvbulkpipe(dev->udev, 148 dev->bulk_in_endpointAddr), 149 dev->bulk_in_buffer, 150 min(dev->bulk_in_size, count), 151 &bytes_read, 10000); 152 153 /* if the read was successful, copy the data to userspace */ 154 if (!retval) { 155 if (copy_to_user(buffer, dev->bulk_in_buffer, bytes_read)) 156 retval = -EFAULT; 157 else 158 retval = bytes_read; 159 } 160 161 return retval; 162 } 163 164 static long lcd_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 165 { 166 struct usb_lcd *dev; 167 u16 bcdDevice; 168 char buf[30]; 169 170 dev = file->private_data; 171 if (dev == NULL) 172 return -ENODEV; 173 174 switch (cmd) { 175 case IOCTL_GET_HARD_VERSION: 176 mutex_lock(&lcd_mutex); 177 bcdDevice = le16_to_cpu((dev->udev)->descriptor.bcdDevice); 178 sprintf(buf, "%1d%1d.%1d%1d", 179 (bcdDevice & 0xF000)>>12, 180 (bcdDevice & 0xF00)>>8, 181 (bcdDevice & 0xF0)>>4, 182 (bcdDevice & 0xF)); 183 mutex_unlock(&lcd_mutex); 184 if (copy_to_user((void __user *)arg, buf, strlen(buf)) != 0) 185 return -EFAULT; 186 break; 187 case IOCTL_GET_DRV_VERSION: 188 sprintf(buf, DRIVER_VERSION); 189 if (copy_to_user((void __user *)arg, buf, strlen(buf)) != 0) 190 return -EFAULT; 191 break; 192 default: 193 return -ENOTTY; 194 break; 195 } 196 197 return 0; 198 } 199 200 static void lcd_write_bulk_callback(struct urb *urb) 201 { 202 struct usb_lcd *dev; 203 int status = urb->status; 204 205 dev = urb->context; 206 207 /* sync/async unlink faults aren't errors */ 208 if (status && 209 !(status == -ENOENT || 210 status == -ECONNRESET || 211 status == -ESHUTDOWN)) { 212 dev_dbg(&dev->interface->dev, 213 "nonzero write bulk status received: %d\n", status); 214 } 215 216 /* free up our allocated buffer */ 217 usb_free_coherent(urb->dev, urb->transfer_buffer_length, 218 urb->transfer_buffer, urb->transfer_dma); 219 up(&dev->limit_sem); 220 } 221 222 static ssize_t lcd_write(struct file *file, const char __user * user_buffer, 223 size_t count, loff_t *ppos) 224 { 225 struct usb_lcd *dev; 226 int retval = 0, r; 227 struct urb *urb = NULL; 228 char *buf = NULL; 229 230 dev = file->private_data; 231 232 /* verify that we actually have some data to write */ 233 if (count == 0) 234 goto exit; 235 236 r = down_interruptible(&dev->limit_sem); 237 if (r < 0) 238 return -EINTR; 239 240 /* create a urb, and a buffer for it, and copy the data to the urb */ 241 urb = usb_alloc_urb(0, GFP_KERNEL); 242 if (!urb) { 243 retval = -ENOMEM; 244 goto err_no_buf; 245 } 246 247 buf = usb_alloc_coherent(dev->udev, count, GFP_KERNEL, 248 &urb->transfer_dma); 249 if (!buf) { 250 retval = -ENOMEM; 251 goto error; 252 } 253 254 if (copy_from_user(buf, user_buffer, count)) { 255 retval = -EFAULT; 256 goto error; 257 } 258 259 /* initialize the urb properly */ 260 usb_fill_bulk_urb(urb, dev->udev, 261 usb_sndbulkpipe(dev->udev, 262 dev->bulk_out_endpointAddr), 263 buf, count, lcd_write_bulk_callback, dev); 264 urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP; 265 266 usb_anchor_urb(urb, &dev->submitted); 267 268 /* send the data out the bulk port */ 269 retval = usb_submit_urb(urb, GFP_KERNEL); 270 if (retval) { 271 dev_err(&dev->udev->dev, 272 "%s - failed submitting write urb, error %d\n", 273 __func__, retval); 274 goto error_unanchor; 275 } 276 277 /* release our reference to this urb, 278 the USB core will eventually free it entirely */ 279 usb_free_urb(urb); 280 281 exit: 282 return count; 283 error_unanchor: 284 usb_unanchor_urb(urb); 285 error: 286 usb_free_coherent(dev->udev, count, buf, urb->transfer_dma); 287 usb_free_urb(urb); 288 err_no_buf: 289 up(&dev->limit_sem); 290 return retval; 291 } 292 293 static const struct file_operations lcd_fops = { 294 .owner = THIS_MODULE, 295 .read = lcd_read, 296 .write = lcd_write, 297 .open = lcd_open, 298 .unlocked_ioctl = lcd_ioctl, 299 .release = lcd_release, 300 .llseek = noop_llseek, 301 }; 302 303 /* 304 * usb class driver info in order to get a minor number from the usb core, 305 * and to have the device registered with the driver core 306 */ 307 static struct usb_class_driver lcd_class = { 308 .name = "lcd%d", 309 .fops = &lcd_fops, 310 .minor_base = USBLCD_MINOR, 311 }; 312 313 static int lcd_probe(struct usb_interface *interface, 314 const struct usb_device_id *id) 315 { 316 struct usb_lcd *dev = NULL; 317 struct usb_endpoint_descriptor *bulk_in, *bulk_out; 318 int i; 319 int retval; 320 321 /* allocate memory for our device state and initialize it */ 322 dev = kzalloc(sizeof(*dev), GFP_KERNEL); 323 if (!dev) 324 return -ENOMEM; 325 326 kref_init(&dev->kref); 327 sema_init(&dev->limit_sem, USB_LCD_CONCURRENT_WRITES); 328 init_usb_anchor(&dev->submitted); 329 330 dev->udev = usb_get_dev(interface_to_usbdev(interface)); 331 dev->interface = interface; 332 333 if (le16_to_cpu(dev->udev->descriptor.idProduct) != 0x0001) { 334 dev_warn(&interface->dev, "USBLCD model not supported.\n"); 335 retval = -ENODEV; 336 goto error; 337 } 338 339 /* set up the endpoint information */ 340 /* use only the first bulk-in and bulk-out endpoints */ 341 retval = usb_find_common_endpoints(interface->cur_altsetting, 342 &bulk_in, &bulk_out, NULL, NULL); 343 if (retval) { 344 dev_err(&interface->dev, 345 "Could not find both bulk-in and bulk-out endpoints\n"); 346 goto error; 347 } 348 349 dev->bulk_in_size = usb_endpoint_maxp(bulk_in); 350 dev->bulk_in_endpointAddr = bulk_in->bEndpointAddress; 351 dev->bulk_in_buffer = kmalloc(dev->bulk_in_size, GFP_KERNEL); 352 if (!dev->bulk_in_buffer) { 353 retval = -ENOMEM; 354 goto error; 355 } 356 357 dev->bulk_out_endpointAddr = bulk_out->bEndpointAddress; 358 359 /* save our data pointer in this interface device */ 360 usb_set_intfdata(interface, dev); 361 362 /* we can register the device now, as it is ready */ 363 retval = usb_register_dev(interface, &lcd_class); 364 if (retval) { 365 /* something prevented us from registering this driver */ 366 dev_err(&interface->dev, 367 "Not able to get a minor for this device.\n"); 368 usb_set_intfdata(interface, NULL); 369 goto error; 370 } 371 372 i = le16_to_cpu(dev->udev->descriptor.bcdDevice); 373 374 dev_info(&interface->dev, "USBLCD Version %1d%1d.%1d%1d found " 375 "at address %d\n", (i & 0xF000)>>12, (i & 0xF00)>>8, 376 (i & 0xF0)>>4, (i & 0xF), dev->udev->devnum); 377 378 /* let the user know what node this device is now attached to */ 379 dev_info(&interface->dev, "USB LCD device now attached to USBLCD-%d\n", 380 interface->minor); 381 return 0; 382 383 error: 384 kref_put(&dev->kref, lcd_delete); 385 return retval; 386 } 387 388 static void lcd_draw_down(struct usb_lcd *dev) 389 { 390 int time; 391 392 time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000); 393 if (!time) 394 usb_kill_anchored_urbs(&dev->submitted); 395 } 396 397 static int lcd_suspend(struct usb_interface *intf, pm_message_t message) 398 { 399 struct usb_lcd *dev = usb_get_intfdata(intf); 400 401 if (!dev) 402 return 0; 403 lcd_draw_down(dev); 404 return 0; 405 } 406 407 static int lcd_resume(struct usb_interface *intf) 408 { 409 return 0; 410 } 411 412 static void lcd_disconnect(struct usb_interface *interface) 413 { 414 struct usb_lcd *dev; 415 int minor = interface->minor; 416 417 mutex_lock(&open_disc_mutex); 418 dev = usb_get_intfdata(interface); 419 usb_set_intfdata(interface, NULL); 420 mutex_unlock(&open_disc_mutex); 421 422 /* give back our minor */ 423 usb_deregister_dev(interface, &lcd_class); 424 425 /* decrement our usage count */ 426 kref_put(&dev->kref, lcd_delete); 427 428 dev_info(&interface->dev, "USB LCD #%d now disconnected\n", minor); 429 } 430 431 static struct usb_driver lcd_driver = { 432 .name = "usblcd", 433 .probe = lcd_probe, 434 .disconnect = lcd_disconnect, 435 .suspend = lcd_suspend, 436 .resume = lcd_resume, 437 .id_table = id_table, 438 .supports_autosuspend = 1, 439 }; 440 441 module_usb_driver(lcd_driver); 442 443 MODULE_AUTHOR("Georges Toth <g.toth@e-biz.lu>"); 444 MODULE_DESCRIPTION(DRIVER_VERSION); 445 MODULE_LICENSE("GPL"); 446